eulerr: Area-Proportional Euler and Venn Diagrams with Circles or
Ellipses

If possible, generates exactly area-proportional Euler diagrams
using numerical optimization. A Euler diagram is a generalization of a Venn
diagram, relaxing the criterion that all interactions need to be
represented. Euler diagrams can be fit with both ellipses and circles from
a wide range of inputs and can be visualized in numerous ways.